Paper
15 November 1999 Design of energy filters for electron microscopes
Katsushige Tsuno
Author Affiliations +
Abstract
Software for simulating 3D electric and magnetic fields followed by the direct ray tracing in individual field and combined fields (EO3D, MO3D and CO3D) are well applied to the design of energy filters attached to electron microscopes. When we had designed a high resolution EELS instrument, we had no 3D software, and encountered problems in designing a retarding Wien filter used as the monochromator and analyzer. At that time, electric field homogeneity inside the gap of magnet and the deflection of beam at the fringing region due to the deviation of the Wien condition were unsolved problems. When we designed a low energy reflection electron microscope (LEEM), we had 3D software, and some of the above problems were solved. We used an arc shaped electrode for the beam separator and an eight-pole filter for the analyzer. The coincidence of the magnetic and electric fringing field distributions at the fringing regions (Wien condition) was not perfect but was improved. We have designed an omega filter for in-column energy filtered transmission electron microscope (EFTEM). The omega filter consists of four sector magnets. Optical behavior of the system is very complicated. First, we designed the filter by 2D approximation and then checked by electron trajectories by the 3D software. The designed omega filter works successfully.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Katsushige Tsuno "Design of energy filters for electron microscopes", Proc. SPIE 3777, Charged Particle Optics IV, (15 November 1999); https://doi.org/10.1117/12.370134
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Cited by 2 scholarly publications.
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KEYWORDS
Optical filters

Magnetism

Electron microscopes

Electrodes

Monochromators

3D applications

Lenses

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